2008 Ford F350 - Cracking The Code

6.4 Liters, Six Speeds, And 600 HP

The last decade of diesel performance hasn't been the easiest for Ford fans wanting to go head-to-head with the competition. Between the extremely complicated HEUI injection system and the Super Duty's performance-hindering weight, Power Stroke owners just couldn't get a break on the street or at events. No one knows that better than Chad Flynn, of Flynn's Shop in Alexander, Illinois. He's been a Blue Oval loyalist his entire life and knows that a 7.3L or 6.0L making serious horsepower comes with a hefty price tag.

After owning a '99 7.3L in his younger years and an '04 6.0L Power Stroke just a short time ago, he's poured a lot of blood, sweat, and tears into his Super Dutys. And after experiencing many of the cooling and head gasket headaches that modified 6.0L Power Strokes are prone to having, he nearly called it quits and traded in for the competition. "A couple of years ago, I about gave up-and if I had, you'd be taking pictures of a 900hp Cummins daily driver," Chad told us.

But when Chad heard International planned to build a twin-turbo, common-rail-injected 6.4L for Ford's '08 Super Duty trucks, he knew he'd be one of the first people around to own one. And not only that, he would get power to the ground the old-fashioned way-with a manual transmission.

The first modification to his F-350 was a Stage 2 cold-air intake from Advanced Flow Engineering. Then, in the blink of an eye, much of the new Power Stroke's performance potential was discovered using Spartan Diesel Technologies' tuning and a 5-inch MagnaFlow exhaust. The newfound power of a 250hp setting immediately turned the $50,000 truck into a play toy. And there were no ifs, ands, or buts about what had to be upgraded next-the clutch.

Within 30 miles of uploading the tune, Chad told us the stock clutch would slip in Sixth gear, and he knew it would never hold. But with an even higher horsepower tune in his possession that he desperately wanted to try, South Bend Clutch got the call. Its answer was a dual-disc unit capable of withstanding up to 750 hp. After that, Chad was able to try out a 275hp tune, which was also from Spartan Diesel.

As you may or may not know, more than 99 percent of 6.4L-powered Super Dutys are equipped with automatic transmissions. Manual versions are not only rare but can handle a lot of horsepower with an aftermarket clutch and are much easier to dyno with. Recently, another group of Power Stroke gurus, River City Diesel, came along and offered to tune Chad's truck. With his truck on the dyno, the River City Diesel guys tried what they called their 311hp race tune and claimed the truck dyno'd 585 hp and 1,185 lb-ft. Not bad for what most would consider basic modifications.

To be honest, there isn't a lot done to the rest of the truck, but that's the beauty of it. The 6.4L makes more power than anyone in the diesel industry ever expected with just an air intake, exhaust, and a programmer. Having a truck with great power potential right out of the box came as a pleasant surprise to Chad. "I had a pretty good idea, with the twin turbos and common-rail injection, but I still didn't know what the motor would be capable of," he told us. "I'm pretty impressed with it so far."

Like everyone else on the common-rail bandwagon, Chad's up for anything that's coming down the pipeline for his Ford. This winter he plans to keep the 6.4L's fuel rails full by running twin injection pumps, which will feed a set of modified piezo injectors. The job of matching all that extra fuel will be left up to an S300 over S400 turbo setup, which is also in the works.

With a list of modifications this serious, look for his truck to come out swinging in the spring of '10. The 6.4L Power Stroke has definitely cracked the power-potential code Ford fans have been after, and for Chad, it's been well worth the wait.